1. Field of the Invention
This invention relates to a vessel used for a reaction vessel or an agitation vessel (hereinafter referred to as "processing vessel") in the field of chemical, petrochemical and food industries and, more particularly, to a processing vessel upon which a large thermal load is imposed during processing, or a processing vessel suitable for manufacturing such a product that heat-removing and heating powers are dominant factors of the productivity with which the product is produced.
2. Description of the Related Art
In general, a processing vessel of this kind is constructed in such a manner that a vessel body is formed as a pressure-proof closed vessel by welding dished end plates or the like to the opposite ends of a cylindrical barrel member, and a temperature control system for removing heat generated in the vessel or for heating a material contained in the vessel is provided in the vessel body.
As conventional heat removing systems for processing vessels, there have been known a jacket system, such as that shown in FIG. 10, in which a jacket 30 is annexed outside a vessel body 1', an inner pipe system, such as that shown in FIG. 11, in which a helical pipe 31 is fixedly disposed inside the internal surface of a vessel body 1', another inner pipe system, such as that shown in FIG. 12, in which a pipe 32 extending mainly along the longitudinal direction of a vessel body 1' inside the inner surface of the vessel body and having its ends elbow-connected is fixedly disposed by being meandered along the circumferential direction of the vessel body, an inner jacket system, such as that shown in FIG. 13, in which partition plates 33 are arranged at certain intervals perpendicularly to the inner surface of a vessel body 1', and inner strips 34 are disposed so as to extend between the inner ends of the partition plates 33, whereby a helical flow passage 35 is formed between the inner strips 34 and the inner surface of the vessel body 1' by being partitioned by the partition plates 33 (Japanese Patent Unexamined Publication No. 57-147502), and other types.
In the jacket system arranged for heat exchange through the wall of the vessel body as shown in FIG. 10, the thickness of the plate forming the vessel body is ordinarily increased in order to set a structural strength large enough to withstand the pressure generated in the vessel body and the jacket, so that the heat transfer rate is disadvantageously low. If the size of the vessel is increased, the thickness of vessel body wall must be increased to obtain the desired strength. Therefore, it is difficult to adapt this type of system to a large vessel.
In the inner pipe system arranged as shown in FIG. 12 or 13 for heat exchange through the wall of the pipe 31 or 32 inside the vessel body 1', the pipe thickness is determined by the pipe diameter, and the pipe diameter is small in comparison with the inside diameter of the vessel body 1'. Therefore, the pipe thickness is small and an improved heat transfer characteristic can be achieved. However, it is possible that contained materials will adhere to the pipe and a support for fixing the pipe to impede heat transfer, and that adhered materials will be mixed in a product, resulting in a reduction in the of the operating efficiency stability and a deterioration in product quality.
In the inner jacket system arranged as shown in FIG. 13 for heat exchange through the inner strips 34 inside the vessel body 1', the drawbacks of the systems of FIGS. 10 to 12 are removed. Also, the thickness of the inner strips 34 is small and an improved heat transfer characteristic can be achieved, because the thickness of the inner strips 34 is determined by the distance between the partition plates 33, and because the distance between the partition plates 33 is small in comparison with the inside diameter of the vessel body 1'. However, laborious operations are required as on site working for assembly inside the vessel to attach partition plates 33 to the inner surface of the vessel body 1' one by one and to thereafter attach inner strips 34 so as to connect the ends of the partition plates 33. Moreover, a multiplicity of welded portions between the inner strips 34 are exposed in the internal surface, and the surface of the welded portions needs smooth finishing. Thus, the manufacturing process is laborious and time-consuming.
Further, if the welded portions contact a corrosive solution, it is necessary to confirm the corroded state and to repair corroded portions if necessary. It is necessary to frequently perform maintenance operations.